Drawing the line

The pea aphid Acyrthosiphon pisum is an agriculturally important pest of leguminous plants including peas and broad beans. The widespread use of chemical pesticides impacts heavily on the environment, and increases pesticide-resistant pea aphid populations, so alternative strategies are being actively sought. Pseudomonas syringae bacteria are known to infect and kill the pea aphid, and offer a possible control strategy. In this study, the authors measured the effects of injecting P. syringae on the survival of pea aphid populations at 24 and 48 hours. The pea aphid population was killed more rapidly (98 % after 24 hours) with a higher concentration of injected bacteria than in the control or with lower concentrations, indicating that a P. syringae-based control strategy may be a useful alternative to conventional pesticides.